In an unexpected move, the commission voted 4-1 Wednesday to close its docket in the case because of doubts about the constitutionality of deregulation. That cancels planned future meetings on the subject.

Under deregulation, customers can choose their suppliers of power, which is still delivered over local utilities’ wires.

Deregulation supporters said it’d foster competition and lower prices, while opponents said unregulated marketplace would create uncertainty and pointed to failed efforts in other states.

Arizona Public Service Co. cited uncertainty from potential deregulation when it delayed a plan to buy Southern California Edison’s portion of the Four Corners Power Plant outside Farmington, N.M.